1. Field of the Invention
The present invention relates to a method for cleaning the disc surfaces and the heads in a magnetic disc drive and, more particularly, to a head cleaning cycle whereby particles embedded on both the heads and the magnetic disc surfaces in a magnetic disc drive may be dislodged.
2. Description of the Prior Art
Magnetic disc storage systems are widely used to provide large volumes of relatively low-cost, computer-accessible memory or storage. A typical disc storage device has a number of discs coated with a suitable magnetic material mounted for rotation on a common spindle and a set of transducer heads carried in pairs on elongated supports for insertion between adjacent discs, the heads of each pair facing in opposite directions to engage opposite faces of the adjacent discs. The support structure is coupled to a positioner motor, the positioner motor typically including a coil mounted within a magnetic field for linear movement and oriented relative to the discs to move the heads radially over the disc surfaces to thereby enable the heads to be positioned over any annular track on the surfaces. In normal operation, the positioner motor, in response to control signals from the computer, positions the transducer heads radially for recording data signals on, or retrieving data signals from, a pre-selected one of a set of concentric recording tracks on the discs.
The transducer heads are supported above the disc surfaces by a film of air to prevent contact therebetween which might otherwise damage one or both members. The heads are typically designed to actually fly above the disc recording surfaces at heights of less than 50 microinches.
Modern magnetic disc drives incorporate rigid substrate discs, the surfaces of which are polished to a high finish so that the heads can reliably fly on the air bearing. Systems are presently being developed wherein the heads fly above the disc recording surfaces at heights of less than 20 microinches. Such a disc drive typically incorporates a filtered air system to control the cleanliness of the head flying environment.
Regardless of the care taken to maintain cleanliness of the head flying environment, the probability remains high that contamination particles may be present in the head flying environment and that such particles may become deposited on either the heads or the disc surfaces. This is especially the case in removable media disc drives wherein a disc pack or cartridge is removed from the disc drive. The presence of these lodged particles may affect the flight attitude of the heads and thereby reduce their ability to record and retrieve data from the disc surfaces. In the extreme, the presence of disc contamination may cause a crash of a flying head, causing destruction of the head and/or disc. Accordingly, it becomes important to provide a method and apparatus for cleaning the disc surfaces and the heads in a magnetic disc drive.